packages, versions and browsers

I am a long-term user of NetBSD, and before that a BSD/OS user and a System
V user, and a version 7 user etc. etc. I use NetBSD both as a
software development environment and as a day-to-day
workstation (and for that matter I run my colocated network servers
on NetBSD too). I chose NetBSD for its reputation for stability, backward
compatibility and code quality. I don't chase the latest gimmicks, I'm
not looking for bleeding-edge experimentation, and I'm not a hobbyist.
I rely on NetBSD to provide my daily computing needs, and to service my
customers and
so earn aliving.
Am I mistaken, or have things started to get awfully complicated when
it comes to some packages? I've recently become convinced that there is a
memory leak in the version of Firefox I've been running, which has
made my personal workstation grind to a near halt. So I thought -
why not update? The labyrinth of nested dependences I have
encountered in the process beggars description, and the more I try to
update packages in the hope of finally downloading or building an
up-to-date version, the more I seem to break other software on which I
depend. Varsion numbers of shared libraries are one common stumbling
block; apparent failure to find files which are plainly present in the
pkgsrc location being searched is another.
The problem is not one of difficulty understanding, it's the intricate
patterns of dependency, and the repeated need for manual intervention
to allow for those patterns.
I had a most difficult time migrating from 4.x to 5.0.2 because of
this kind of problem, and still run 3.x and 4.x on the systems that
earn my living lest upgrading cost me days of effort.
So am I missing a trick somewhere? How do other people manage the
transition from one release to another while protecting the
functionality of existing software? And is there a way of running a
web browser on NetBSD that doesn't just grow and grow?
--
Steve Blinkhorn <steve%prd.co.uk@localhost>